Parking Brake System

A parking lock device (1) for a power train of a motor vehicle with an automatic transmission, the device (1) comprising:

• a locking mechanism (3) operated by an actuator (2),
• the locking mechanism (3) having an engaged condition in which the power take-off of the power train rotationally fixed, and a disengaged condition in which the power take-off of the power train is rotatable;
• a piston unit (5) of the actuator (2) engaging the locking mechanism in a normal operation mode of the motor vehicle, when pressurized with a fluid in an engaging direction of the locking device against a spring device (6) which is engaged with the piston unit (5), the piston unit is held in the disengaged position by a snap-in locking device (8) which is controlled by an electromagnetic actuator (7), which fixes the piston unit (5) in an active condition at a first axial position (A) equivalent to the disengaged condition of the locking mechanism (3),
• the snap-in locking device (8) is deactivated by the electromagnetic actuator (7);
• an emergency locking device (9) manually engages the locking mechanism (3) and an emergency unlocking device (10) disengages the locking mechanism (3);
• and
• a common actuator mechanism (11) operates the emergency unlocking device (10) and the emergency locking device (9) so that manual activation of the actuator mechanism (11) in the same operating direction alternatively disengages or engages the locking mechanism (3).